body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

.editor-container {
    display: flex;
    height: 100vh;
}

textarea#markdown-input, div#html-preview {
    width: 50%;
    height: 100%;
    padding: 20px;
    box-sizing: border-box;
}

textarea#markdown-input {
    resize: none;
    border: none;
    outline: none;
    background-color: #fff;
    font-size: 16px;
    line-height: 1.5;
}

div#html-preview {
    background-color: #fff;
    overflow-y: auto;
    border-left: 1px solid #ddd;
}

td.hljs-ln-line.hljs-ln-numbers {
    padding-right: 10px;
}